Veterinarians On Call

The importance of high health has long been recognized in all facets of pork production. The ongoing challenge is to eliminate specific pathogens from a herd whenever possible. The best strategies center on early weaning and multi-site production.Actinobacillus pleuropneumonia, pseudorabies virus (PRV), transmissible gastroenteritis (TGE), Pasteurella multocida (type D) and swine dysentery are just

Keith Wilson, DVM | Feb 01, 1999

The importance of high health has long been recognized in all facets of pork production. The ongoing challenge is to eliminate specific pathogens from a herd whenever possible. The best strategies center on early weaning and multi-site production.

Actinobacillus pleuropneumonia, pseudorabies virus (PRV), transmissible gastroenteritis (TGE), Pasteurella multocida (type D) and swine dysentery are just some of the diseases that have been eliminated using various clean-up methods.

But two bacteria, Streptococcus suis and Haemophilus parasuis have survived the most aggressive approaches. These bacteria have found a way to hide comfortably within healthy, carrier pigs and, when given the opportunity, emerge and cause significant losses.

Strep suis and Haemophilus parasuis are tw o of the most common and most frustrating diseases present in nursery pigs. They show up following a stressful event or in early weaning situations where natural exposure does not occur until they are away from the sow. Establishing immunity within a herd and a group of pigs is difficult but important for control.

The source farm recently had an acute outbreak of swine influenza virus (SIV). This producer received pigs at the start of the outbreak. The pigs looked healthy and normal at weaning, but the day following arrival a widespread cough affected virtually all of the pigs. Except for the occasional pig that needed treatment because it was thumping, the pigs' activity level and appetite remained good. Death loss was low and the pigs recovered within 7-10 days.

It was our clinical impression that this nursery had experienced an SIV outbreak consistent with what was seen at the source farm during shipping.

About four weeks later, we were called back to examine pigs that were developing an acute lameness. The producer noted he had treated five pigs the day before. He had sorted off 10-12 pigs with swollen and warm joints. Some showed only a small amount of lameness but others would not put weight on the affected leg.

We sacrificed a pig and submitted it to the laboratory. We recommended injectable ampicillin to the affected pigs and the addition of amoxicillin to the water for three days.

The laboratory isolated a Strep suis (type 2) from one of the infected joints. Antibiotic sensitivities indicated that amoxicillin and ampicillin were two of the antibiotics of choice. We were successful in reducing new infections, but only about 20% of the pigs responded well enough to be put back with the other pigs. When this nursery eventually closed out, this producer reported 4% death loss with about 3% of it due to the acute Strep infection that was affecting the joints.

Case Study No. 2 Our second farm case was a 300-sow, farrow-to-finish operation. We were called to investigate an increase in nursery death loss. Death loss over the last turn was 7%, but the death loss and sick pigs were continuing into the next group. Affected pigs became very tender and sore and their hair coat became very rough. The pigs were scattered throughout the room and did not appear to be from any particular pen or area of the nursery.

We took two pigs to the laboratory for a work-up. Immediately on the post-mortem exam, there was a large amount of fluid in all of the body cavities with an abundance of fibrin. This had the classic appearance of Glasser's disease, which is caused by Haemophilus parasuis. The laboratory confirmed it.

Glasser's disease is a systemic infection affecting the surface of the organs and intestines as well as causing arthritis and meningitis. The laboratory report indicated that the bacteria were sensitive to Excenel. Our recommendations were to treat at the first signs of infection with the once-a-day treatment for three days. We had success with this treatment as long as we caught the infection early.

For future farrowings, we recommended vaccination of the sows before farrowing with a Haemophilus parasuis vaccine. We also felt vaccination of piglets at day 7-10, and again at weaning, was helpful for nursery control.

Our long-term goal is to increase the sow herd immunity enough to eliminate piglet vaccination. If the nursery is managed all-in, all-out and there is good environmental management, this program will likely be successful.

Case Study No. 3 This case is a 600-sow, farrow-to-finish farm that weans off site at 10-12 days of age. Overall herd health is excellent. Death loss in the nursery runs 1-2%. However, occasionally there will be a group where death loss will jump to 5-7%. Post-mortems consistently reveal Strep suis isolation.

The death loss happens quickly with most pigs dying within three days. We didn't want to medicate every group,due to the difficulty in predicting which group would be affected, but we were frustrated with the high death loss.

At the first sign of a typical Strep-caused death, we medicated the water with amoxicillin for three days. We also injected every pig in the room with 1 cc. of penicillin. There would be high death loss the first day but dramatically decreased loss the following days. Though this program was not 100% effective, it did reduce death loss with minimum cost.